From patchwork Mon Dec 11 12:18:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 13487142 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="T3qSwIEv" Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23B42100; Mon, 11 Dec 2023 04:20:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1702297213; x=1733833213; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=cxNgVJ/PcdwvPUNXmgeYJWokNuSFkR1LsjZSrf4aHqw=; b=T3qSwIEvzxU3k2xcCrxZMVR3wldRKIpMosRxqgMcvA/ee4nDikOJdNCH S0AEBFvJKY96aFMlNm6lHgsB6M5dYwf7QkaEdJ//T4LYT11/KYefmNfOH oswygmwUc2iwuKpiGXzOeUHqK/7JksGnNAK3GtnvzY2wiFsO7X6NJJwN9 hkYBfyim1ABI52Ap/0uhZ+ZoAF33l8u7RnkxOsg6AUZQaKViHkkSsNqzs hxx/oElWZ29QQd9+oYGR7nSl15liUm4B3oL5zJo/j1uDVOU+KybYXr0kZ jcrtj8E74qfDIZpeSAQTvQ8O9n1MOg0MUa5lrpPsXDE3+le/2odoaMj2O A==; X-IronPort-AV: E=McAfee;i="6600,9927,10920"; a="374797142" X-IronPort-AV: E=Sophos;i="6.04,267,1695711600"; d="scan'208";a="374797142" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Dec 2023 04:20:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10920"; a="896441099" X-IronPort-AV: E=Sophos;i="6.04,267,1695711600"; d="scan'208";a="896441099" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.246.50.188]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Dec 2023 04:20:07 -0800 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-kselftest@vger.kernel.org, Reinette Chatre , Shuah Khan , Shaopeng Tan , =?utf-8?q?Maciej_Wiecz=C3=B3r-R?= =?utf-8?q?etman?= , Fenghua Yu Cc: linux-kernel@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= Subject: [PATCH v3 10/29] selftests/resctrl: Exclude shareable bits from schemata in CAT test Date: Mon, 11 Dec 2023 14:18:07 +0200 Message-Id: <20231211121826.14392-11-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20231211121826.14392-1-ilpo.jarvinen@linux.intel.com> References: <20231211121826.14392-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 CAT test doesn't take shareable bits into account, i.e., the test might be sharing cache with some devices (e.g., graphics). Introduce get_mask_no_shareable() and use it to provision an environment for CAT test where the allocated LLC is isolated better. Excluding shareable_bits may create hole(s) into the cbm_mask, thus add a new helper count_contiguous_bits() to find the longest contiguous set of CBM bits. create_bit_mask() is needed by an upcoming CAT test rewrite so make it available in resctrl.h right away. Signed-off-by: Ilpo Järvinen Reviewed-by: Reinette Chatre --- v3: - Tweak comments - Make get_shareable_mask() static --- tools/testing/selftests/resctrl/cat_test.c | 12 ++- tools/testing/selftests/resctrl/resctrl.h | 2 + tools/testing/selftests/resctrl/resctrlfs.c | 89 +++++++++++++++++++++ 3 files changed, 99 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index f18c95dda5d3..1e3c5432ecff 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -89,15 +89,19 @@ void cat_test_cleanup(void) int cat_perf_miss_val(int cpu_no, int n, char *cache_type) { + unsigned long full_cache_mask, long_mask; unsigned long l_mask, l_mask_1; int ret, pipefd[2], sibling_cpu_no; unsigned long cache_total_size = 0; - unsigned long long_mask; int count_of_bits; char pipe_message; size_t span; - ret = get_full_cbm(cache_type, &long_mask); + ret = get_full_cbm(cache_type, &full_cache_mask); + if (ret) + return ret; + /* Get the largest contiguous exclusive portion of the cache */ + ret = get_mask_no_shareable(cache_type, &long_mask); if (ret) return ret; @@ -136,7 +140,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type) /* Set param values for parent thread which will be allocated bitmask * with (max_bits - n) bits */ - span = cache_portion_size(cache_total_size, l_mask, long_mask); + span = cache_portion_size(cache_total_size, l_mask, full_cache_mask); strcpy(param.ctrlgrp, "c2"); strcpy(param.mongrp, "m2"); strcpy(param.filename, RESULT_FILE_NAME2); @@ -158,7 +162,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type) param.mask = l_mask_1; strcpy(param.ctrlgrp, "c1"); strcpy(param.mongrp, "m1"); - span = cache_portion_size(cache_total_size, l_mask_1, long_mask); + span = cache_portion_size(cache_total_size, l_mask_1, full_cache_mask); strcpy(param.filename, RESULT_FILE_NAME1); param.num_of_runs = 0; param.cpu_no = sibling_cpu_no; diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 0e3a4da5f6ec..40baebb066aa 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -98,7 +98,9 @@ void tests_cleanup(void); void mbm_test_cleanup(void); int mba_schemata_change(int cpu_no, const char * const *benchmark_cmd); void mba_test_cleanup(void); +unsigned long create_bit_mask(unsigned int start, unsigned int len); int get_full_cbm(const char *cache_type, unsigned long *mask); +int get_mask_no_shareable(const char *cache_type, unsigned long *mask); int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size); void ctrlc_handler(int signum, siginfo_t *info, void *ptr); int signal_handler_register(void); diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 65e149038248..35425d00ede6 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -228,6 +228,44 @@ static int get_bit_mask(const char *filename, unsigned long *mask) return 0; } +/* + * create_bit_mask- Create bit mask from start, len pair + * @start: LSB of the mask + * @len Number of bits in the mask + */ +unsigned long create_bit_mask(unsigned int start, unsigned int len) +{ + return ((1UL << len) - 1UL) << start; +} + +/* + * count_contiguous_bits - Returns the longest train of bits in a bit mask + * @val A bit mask + * @start The location of the least-significant bit of the longest train + * + * Return: The length of the contiguous bits in the longest train of bits + */ +static unsigned int count_contiguous_bits(unsigned long val, unsigned int *start) +{ + unsigned long last_val; + unsigned int count = 0; + + while (val) { + last_val = val; + val &= (val >> 1); + count++; + } + + if (start) { + if (count) + *start = ffsl(last_val) - 1; + else + *start = 0; + } + + return count; +} + /* * get_full_cbm - Get full Cache Bit Mask (CBM) * @cache_type: Cache type as "L2" or "L3" @@ -254,6 +292,57 @@ int get_full_cbm(const char *cache_type, unsigned long *mask) return 0; } +/* + * get_shareable_mask - Get shareable mask from shareable_bits + * @cache_type: Cache type as "L2" or "L3" + * @shareable_mask: Shareable mask returned as unsigned long + * + * Return: = 0 on success, < 0 on failure. + */ +static int get_shareable_mask(const char *cache_type, unsigned long *shareable_mask) +{ + char mask_path[PATH_MAX]; + + if (!cache_type) + return -1; + + snprintf(mask_path, sizeof(mask_path), "%s/%s/shareable_bits", + INFO_PATH, cache_type); + + return get_bit_mask(mask_path, shareable_mask); +} + +/* + * get_mask_no_shareable - Get Cache Bit Mask (CBM) without shareable bits + * @cache_type: Cache type as "L2" or "L3" + * @mask: The largest exclusive portion of the cache out of the + * full CBM, returned as unsigned long + * + * Parts of a cache may be shared with other devices such as GPU. This function + * calculates the largest exclusive portion of the cache where no other devices + * besides CPU have access to the cache portion. + * + * Return: = 0 on success, < 0 on failure. + */ +int get_mask_no_shareable(const char *cache_type, unsigned long *mask) +{ + unsigned long full_mask, shareable_mask; + unsigned int start, len; + + if (get_full_cbm(cache_type, &full_mask) < 0) + return -1; + if (get_shareable_mask(cache_type, &shareable_mask) < 0) + return -1; + + len = count_contiguous_bits(full_mask & ~shareable_mask, &start); + if (!len) + return -1; + + *mask = create_bit_mask(start, len); + + return 0; +} + /* * get_core_sibling - Get sibling core id from the same socket for given CPU * @cpu_no: CPU number